[Ranchero50]

Need some help on my 308. It almost made some part last Thursday, then the spindle encoder died. EMI-INC is having trouble finding one so I'm looking for a source.

Metric Encoder
58mm servo mount (finger clamped)
6mm shaft
1024 PPR
A
A-
B
B-
5vdc
GND

I've seen some on line, but not much for prices or acturally having them (headache now)

Thanks in advance,
Jamie

[Al_The_Man]

That is the same dimensions as many Heidenhains. Also Hengstler make an equivalent.
You may find the first one on ebay, but for new, the Hengstler would be the cheapest.
The only thing to watch out for in the Heidenhain, is they are not all TTL, If you find one, I can tell you if it is compatible.
Usually I only like to buy off ebay if it is new or NOS, as I have been bitten in the past.
Al.

[Ranchero50]

Thanks Al, a Heidenhain went off last night about twenty miles from me, but it was a 5000ppr and the drive would accept one that fine... I broused eBay and it's scary what
people are selling.

Jamie

[Al_The_Man]

Is that the one the guy has three for sale? ROD 476? These are TTL output,
You would have to change your scaling parameter.
But it should work.
Al.

[Cartesian-xyz]

Ranchero50

Checkout this site in Northern Idaho www.encoder.com
They helped me match up my axis encoder on my OLD
Bridgeport BTC-1. They were very reasonably priced
and great people to work with. They have LOTS of different
shaft sizes, mounts, PPR ect.......

Stephen

[Ranchero50]

Thanks Stephen, they were one of the groups I contacted. Seems like I can get a new one for $330 - 370 with a 3-5 week wait through any one of several companies...

I troubleshot mine and the emmiter LED was dead (wasn't seeing any state change on the reciever diodes while blocking the light) It's off to ACS Industrial Services here in MD for a repair or at least a free quote.

I ended up with this little gem...

http://cgi.ebay.com/ws/eBayISAPI.dll...tab%3DWatching

I can tune the pulse count through the drive and may have to play with the cable mounting since the fan sits above the encoder. It's gonna be custom regardless.

Jamie

[Ranchero50]

Finally can bring this a close. My 308 has a Unidrive spindle motor VFD. The eBay encoder showed up and I had to rework the casing (lathework) so it would fit under the fan and the wiring would work (side exit vs top), then solder the wires together correctly. Powered it up and the drive saw it move. Set the parameters up for 2500 pulse per revolution encoder vs a 1024ppr and gave it a speed command of 1000rpm and it ran up to 750rpm on the monitor display. That had me scratching my head until I realized that with the higher pulse count encoder the drive couldn't read the pulses fast enough so it limited the motor from 8000rpm to 6000rpm so my voltage command was referenced at 75% of speed (smart drive). Had to go into the drive parameters after printing out 300 or so pages of manual and play with the input voltage scalling until the input rpm equalled the output rpm. So now I'm limited to 8000rpm of spindle speed vs 10,000rpm until the original encoder gets repaired. Regardless I only run around 3500rpm while making the parts. Just threw this up here so you guys saw what was involved to get it back up and making parts with the wrong encoder. I'd also like to give Mark and Bart from EMI-INC kudos for their help troubleshooting this problem which they've never had to chase down before even though there are a bunch of 308's with this retro still running around. It was educational.

Jamie